How many cements should dentists keep stocked?

Anyone who went to kindergarten knows the kid with the biggest crayon box wins. True, the job of coloring can get done with a simple eight-count box. But 16-, 32- and even 64-count boxes were more desirable. These days, Crayola even makes a 120-count box. But at some point, having more crayons than one needs is just bragging rights. After all, what can “sepia” do that “brown” can’t?

It’s a similar case for dentists and their syringes of cements. While it’s true that dentists need the right tool for the job, it’s also true that the right tool can be used for more than one job.

Adhesion

Ideally, one cement could cover all indications. However, that’s not the case-at least not just yet.

A lot of this comes down to what type of restorative material is being placed.

“On the adhesive side for direct dentistry, we are closer to a universal solution than the cement side,” says Dr. Jason Goodchild, DMD, director of clinical affairs for Premier Dental. “The problem is when you look at the best restorative material, is it composite? Is it amalgam? Is it glass ionomer? Is it zirconia? Is it porcelain?”

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As restorative materials evolve, so do adhesives’ requirements.

“I think everybody wants to move toward this idea of bioactive or biocompatible,” Dr. Goodchild says. “You’re moving toward something that helps the tooth regrow, helps give the tooth back what it lost. Amalgam wasn’t it-that’s silver, that’s metal. Then there’s composite-that’s plastic. Then there is glass ionomer, which, maybe, is a little bit closer but has some intraoral solubility issues, esthetic issues, strength issues. I don’t know if we’ve really found the most ideal restorative material. Wouldn’t it be nice if we could regrow a tooth? That would be outstanding, but we’re not there either.

“On the direct restorative side, I think adhesives are closer to getting you one bottle that can do almost anything,” Dr. Goodchild adds.

Cementation

The need for different types of cements can come down to the indications for which they’re used and their chemical formulation.

“It’s the material family: Metal-oxides, glass-ceramics and metals are very different and require cementation protocols that suit their characteristics best,” says Augusto Robles, DMD, MS, associate professor and director of operative dentistry curriculum at the University of Alabama at Birmingham School of Dentistry says. “Usually glass ionomer, resin-modified glass ionomer, ion-releasing cements and resin cements.”

Doctors have a number of variables to juggle, including the restoration material, the environment and the tooth preparation.

“Picking cements for crowns, inlays, onlays, veneers, stuff like that, isn’t just based on the substrate, the type of crown,” Dr. Goodchild explains. “It could be based on the amount of tooth you have left, the preparation that the doctor did. The prep can really be a determining factor in your cement choice. Preps that are very short or over tapered require a lot more bond strength than ones that are longer and more parallel. So, not only picking a cement based on whether you can achieve moisture control or whether you need esthetics or how much bond strength you need, another determining factor is what kind of preparation were you able to create? Was it very short, over tapered, or was it long and parallel? Long and parallel, you could put any cement in there and it’s going to work. But short and over tapered, you’d better use the strongest cement you can because you’re depending on the cement to do all the work for you.”

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Because of those variables, doctors are going to need more than just one cement.

“There are a lot of factors to determine which cement to use and, ultimately, that’s another reason that we can’t just have one cement,” Dr. Goodchild says. “Most of the time, when you get the strongest cements, they’re also the hardest to work with. The ones that are easy to work with are not always so strong. Again, we have not found the magic bullet.”

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“Well, how many types of cements do I need for my crown and bridge procedures?” Dr. Goodchild contemplates. “Those are the crowns, bridges, posts, inlays, onlays and implants.  I’m looking forward to the day when you really could have one material or product that could do everything. That would be great for efficiency; that would be great for inventory management; that would be great for everybody in the office knowing what to do, how to use that product, because if you have multiple providers, multiple assistants, it’s easy to train people on one thing, one set of directions, instead of multiple sets of directions.”

Doctors may also supplement their armamentaria based on necessary colors and the ability to give ease of use options.

“A resin cement that has try-in pastes and multiple shades might be necessary in practices where minimal prep veneers are done,” Dr. Robles says.

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While doctors could streamline and simplify their workflows with fewer, possibly more multipurpose products, Dr. Goodchild says a lot of that resistance comes down to an unwillingness to step outside one’s comfort zone.

“Most dentists are creatures of habit,” Dr. Goodchild says. “‘I’ve always used this, it’s always worked great for me, so I’m going to use it, even though it’s an older product.’ Most dentists probably have several adhesive products for their indirect restorations.

“On the cement side, you’ve got to have at least two cements, if not more,” he continues. “Dentists need to have some type of a resin cement, and then they need to have some type of a conventional cement. They need something that’s resin-based for strength and esthetics, and then they need a non-resin, conventional-usually glass ionomer-for times where moisture control could be a little bit difficult, access could be a little bit difficult.
Then, if you do veneers, you might want a special veneer cement. If you do implants and cement crowns on implants, you might want another cement.  For example, if you’re going to do a ceramic/glass restoration, e.max crown, you need a resin because you need the strength and esthetics.”

If you do a lot of metal or zirconia, and your preps are good, you may be able to get away with a conventional cement, like a resin-modified glass ionomer, or some of the new bioactive cements.

“For my own practice, when I’ve done posterior crowns with zirconia, I have used conventional cement – RMGI or calcium aluminate, like Ceramir^® (Doxa) or Calibra^® Bio (Dentsply Sirona),” Dr. Goodchild says. “When I do something esthetic in the anterior with glass or ceramic, you’ve got to use resin. It’s strong, it’s esthetic, and it’s made for those types of crowns.”

Ease of use

There’s a trend toward formulations moving to all-in-one, universal systems.

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“With the advent of the universal systems, the armamentarium can be tremendously simplified,” Dr. Robles says. “One resin-modified glass ionomer cement will be sufficient for all circumstances where bonding cannot be done. A universal adhesive with a resin cement will cover most situations when bonding is desired.”

Selecting the right cement requires balancing strength and ease of use. Strength, of course, is ideal for best outcomes, but the strongest material won’t matter if it’s difficult to place or mishandled.

“Most dentists need to have one on either side of that continuum-the strength and the esthetics of a resin versus the moisture tolerance and ease of use that comes with a conventional cement,” Dr. Goodchild says. “And even in the face of peer-reviewed literature or scientific evidence to show that maybe one is better than another, somebody might say, ‘This is what I’ve always used. It’s always worked great in my hands and I’m going to continue doing it that way.’ Dentists very much have a ‘This is what works best in my hands’ attitude.”

Dr. Goodchild hears those sentiments, but suggests those dentists broaden their horizons to try something new.

“I hear that from dentists and I say, ‘That’s great, and I respect that. I don’t want to disrupt your great results, but if we can put something else in your hands that may get you better results, would you at least be open to trying it?’ And that seems to be a nice approach to people to say, ‘Use what you’re using, but are you open to trying something that could give you even better results?’ Materials science moves so fast, and we are coming up with new stuff all the time. So, finding the next thing that works great in your hands is key,” Dr. Goodchild says.

It would be great if doctors only needed one syringe of cement to get their work done. Unfortunately, not every case is the same. Different indications, preps and substrates require different products. But that isn’t to say that doctors need the biggest box of crayons on the playground.